Post by Sabre52 on Jan 21, 2012 15:56:25 GMT -5
Howdy folks,
One of our members asked me to post a tutorial for finishing cabs in a tumbler so here goes.
First off the tumbler in question must be a vibe tumbler as rotaries change the contours of the workpiece too much and are generally not gentle enough for finishing cabs. The cabs done by this method must be of agate/jasper hardness and homogeneous in structure because the vibe will undercut mixed hardness material ( ie dino bone) in fine grind.
I always start as I would with any other cab, with a preform approx 3/16 to 1/4 inch thick and template the cab shape I want. I grind to shape until the line is pretty much gone.
I then mark my bezel at 1/8 inch and dop onto a plastic dop with 3M outdoor double faced tape ( way better than wax especially in cold weather).
Then I go to my diamond wheels and cut the crown with the 220 and do a little work on the 280 to remove any major scratches. The cab then goes into the vibe ( in my case a UV-10) with a whole lot of ceramic media as filler. I generally finish about 50 cabs at a time in the UV.
Usually I run fine grind 110/220 or 220 graded for two days. the cabs when they come out should show no scratches under magnification. If they do, another day may be required but you want this stage as short as possible so your cab outlines are not much altered. The cabs coming out of fine grind should just look kind of frosted or hazy but no scratches.
Next step is prepolish with tripoli and here I put in the fifty cabs with the whole tub full of tiny stones that are already polished. You can include plastic beads too if you like but since none of the tiny stones should have enough mass to chip your cabs, this is really not necessary. The tiny stones act to both cushion the load and provide lots of surface to surface contact so your cabs get well polished. I've heard you can use ceramic, but not the ones from fine grind, in place of the tiny stones but I have tons of tiny stones so use them as they are very smooth. I do prepolish five days and then go to Rockshed AO final polish for five days with the small stones going right through both batches after being washed between stages.
I then clean the stones and cabs and put back in for a one day or less, burnish in Dreft baby soap. You should get results like this. Contours should remain the same and the cool thing is the cabs have slight rounded edges for mounting and are polished front, back and edges. If I've missed anything feel free to ask questions....Mel
One of our members asked me to post a tutorial for finishing cabs in a tumbler so here goes.
First off the tumbler in question must be a vibe tumbler as rotaries change the contours of the workpiece too much and are generally not gentle enough for finishing cabs. The cabs done by this method must be of agate/jasper hardness and homogeneous in structure because the vibe will undercut mixed hardness material ( ie dino bone) in fine grind.
I always start as I would with any other cab, with a preform approx 3/16 to 1/4 inch thick and template the cab shape I want. I grind to shape until the line is pretty much gone.
I then mark my bezel at 1/8 inch and dop onto a plastic dop with 3M outdoor double faced tape ( way better than wax especially in cold weather).
Then I go to my diamond wheels and cut the crown with the 220 and do a little work on the 280 to remove any major scratches. The cab then goes into the vibe ( in my case a UV-10) with a whole lot of ceramic media as filler. I generally finish about 50 cabs at a time in the UV.
Usually I run fine grind 110/220 or 220 graded for two days. the cabs when they come out should show no scratches under magnification. If they do, another day may be required but you want this stage as short as possible so your cab outlines are not much altered. The cabs coming out of fine grind should just look kind of frosted or hazy but no scratches.
Next step is prepolish with tripoli and here I put in the fifty cabs with the whole tub full of tiny stones that are already polished. You can include plastic beads too if you like but since none of the tiny stones should have enough mass to chip your cabs, this is really not necessary. The tiny stones act to both cushion the load and provide lots of surface to surface contact so your cabs get well polished. I've heard you can use ceramic, but not the ones from fine grind, in place of the tiny stones but I have tons of tiny stones so use them as they are very smooth. I do prepolish five days and then go to Rockshed AO final polish for five days with the small stones going right through both batches after being washed between stages.
I then clean the stones and cabs and put back in for a one day or less, burnish in Dreft baby soap. You should get results like this. Contours should remain the same and the cool thing is the cabs have slight rounded edges for mounting and are polished front, back and edges. If I've missed anything feel free to ask questions....Mel